lithograving - Special thanks for your splendid images that bring out the full beauty of engraved stamps.
Michel is wrong in saying that #666 and #667 had comb perforations because all stamps printed on diestamp print presses have harrow perforations
. Besides, they could have been printed on a Johnston press - hardly anyone remembers which diestamp print press printed which stamps then.
Stickney presses used line perforation and collectors often complained about poor quality perfs in the early 1950s, which was explained by the inadequate quality of paper that had to be used to extract ink from the printing cylinder of the old rotary presses.
The problem was finally solved by purchasing the new WIFAG press in the second half of 1951.
On the other hand, stamps printed by photogravure required a different quality of printing paper and no complaints were raised about their comb perforations.
As for the PRAVDA Printing Works, Bratislava, its first post-WWII stamps appeared in 1946 (see http://www.filaso.cz/katalog-znamky...ku-do-vlasti
) and its last ones were the Zápotocký definitives (see http://www.filaso.cz/katalog-znamky...in-zapotocky
). PRAVDA, a large enterprise, could have printed anything from stamps to newspapers, magazines and books then.
Two more photogravure issues appeared: the Stalin Monument in 1955 (part of the Liberation set, see http://www.filaso.cz/katalog-znamky...skoslovenska
) and the Army Exbibition, Prague 1956 (see http://www.filaso.cz/katalog-znamky...brana-vlasti
). Both issues were printed by the Post Office Printing Works, Prague and harrow perforations were used.